Laundry treating appliance and method of detecting oversuds

ABSTRACT

A method for detecting an oversuds condition that can lead to a suds lock condition in a laundry treating appliance includes determining a baseline fill level prior to introducing wash liquid in the cycle of operation; sampling fill levels of the wash liquid during a wash phase of the cycle of operation while wash liquid is being drained; comparing each sampled fill level to the baseline fill level and determining a difference; continuing to sample fill levels for a predetermined period after the difference equals zero; identifying a minimum fill level for the predetermined period; sampling a final fill level after the predetermined period; calculating a difference between the minimum fill level and the final fill level; and identifying a potential suds lock condition if the difference exceeds a predetermined threshold.

BACKGROUND OF THE INVENTION

Laundry treating appliances, such as clothes washers, typically include a tub in which is mounted a rotatable wash basket which receives laundry for treatment according to a cycle of operation. In a typical wash cycle, the laundry is often treated with a laundry detergent or other wash aid that includes surfactants. These surfactants may mix with liquid on the laundry and in the tub to generate suds. In some cases, the generation of suds may generate a suds lock condition and interfere with the rotation of the wash basket, thereby limiting the speed at which the wash basket may be rotated.

BRIEF DESCRIPTION

A method for detecting an oversuds condition that may lead to a suds lock condition in a laundry treating appliance having a tub defining an interior, with a wash basket rotatably mounted within the interior and at least partially defining a treating chamber for receiving laundry for treatment in accordance with a cycle of operation using a wash liquid. The method comprises determining a baseline fill level in the treating chamber prior to introducing wash liquid into the treating chamber in the cycle of operation; sampling fill levels of the wash liquid in the treating chamber during a wash phase of the cycle of operation while wash liquid is being drained from the treating chamber; comparing each sampled fill level to the baseline fill level and determining a difference; continuing to sample fill levels in the treating chamber for a predetermined period after the difference equals zero; identifying a minimum fill level in the treating chamber for the predetermined period; sampling a final fill level after the predetermined period; calculating a difference between the minimum fill level and the final fill level; and identifying an over suds condition that can lead to a suds lock condition if the difference exceeds a predetermined threshold.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic cross-sectional view of a laundry treating appliance according to one embodiment of the invention.

FIG. 2 is a schematic view of a controller of the laundry treating appliance of FIG. 1.

FIG. 3 is a flowchart illustrating a method for detecting an over suds condition according to an embodiment of the invention.

FIG. 4 is a graphical representation of a treating chamber fill level profile according to an embodiment of the invention.

DESCRIPTION

Referring now to the figures, FIG. 1 is a schematic view of an exemplary laundry treating appliance 10 in the form of a washing machine according to one embodiment of the invention. While the laundry treating appliance 10 is illustrated as a vertical axis, top-fill washing machine, the invention may have applicability in other laundry treating appliances, such as a horizontal washing machine, combination laundry treating appliance and dryer, an extractor, a non-aqueous laundry treating appliance, and a tumbling or stationary refreshing/revitalizing machine, for example.

The washing machine 10 may include a cabinet or housing 12 and an imperforate tub 14 that defines an interior 15 of the washing machine 10. A sump 16 may be in fluid communication with the interior 15 of the tub 14. A drum or perforated wash basket 18 may be located within and rotatable relative to the interior 15 of the tub 14 and may define a laundry treating chamber 19 for receiving a laundry load. The wash basket 18 may include a plurality of perforations or apertures (not shown) such that liquid supplied to the wash basket 18 may flow through the perforations to the tub 14. An agitator or clothes mover 20 may be located within the laundry treating chamber 19 and rotatable relative to and/or with the wash basket 18.

The wash basket 18 and/or the clothes mover 20 may be driven by an electrical motor 22, which may or may not include a gear case, operably connected to the wash basket 18 and/or the clothes mover 20. The clothes mover 20 may be commonly oscillated or rotated about its axis of rotation during a cycle of operation in order to produce high water turbulence effective to treat the fabric load contained within the laundry treating chamber 19. The wash basket 18 may be rotated at high speed to centrifugally extract liquid from the fabric load and to discharge it from the wash basket 18. The top of the housing 12 may include a selectively openable lid 24 to provide access into the laundry treating chamber 19 through the open top of the wash basket 18.

Still referring to FIG. 1, a spraying system 30 may be provided to spray liquid, such as water or a combination of water and one or more treating agents into the open top of the wash basket 18 and onto laundry placed within the laundry treating chamber 19. Non-limiting examples of treating chemistries that may be dispensed by the dispensing system during a cycle of operation include one or more of the following: water, surfactants, enzymes, fragrances, stiffness/sizing agents, wrinkle releasers/reducers, softeners, antistatic or electrostatic agents, stain repellants, water repellants, energy reduction/extraction aids, antibacterial agents, medicinal agents, vitamins, moisturizers, shrinkage inhibitors, and color fidelity agents, and combinations thereof.

The spraying system 30 may be configured to supply water directly from a household water supply 32 and/or from the tub 14 and spray it onto the laundry through a sprayer 33. The spraying system 30 may also be configured to recirculate wash water from the tub 14, including the sump 16, and spray it onto the laundry. The spraying system 30 can also include additional sprayers and other components to supply liquid to one or more additional locations, such as a portion of the interior 15 between the wash basket 18 and the tub 14, an exterior surface of the wash basket 18, an interior surface of the wash basket 18 and an internal surface of the tub 14. The nature of the spraying system is not germane to the invention, and thus any suitable spraying system may be used with the laundry treating appliance 10.

A pump 34 may be housed below the tub 14. The pump 34 may have an inlet fluidly coupled to the sump 16 and an outlet configured to fluidly couple to either or both a household drain 36 or a recirculation conduit 38. In this configuration, the pump 34 may be used to drain or recirculate liquid in the sump 16, which is initially sprayed into the wash basket 18, flows through the wash basket 18, and then into the sump 16. Alternatively, two separate pumps may be used instead of the single pump as previously described.

As used herein, the term wash liquid refers to a combination of water and one or more treating agents capable of generating suds. The terms rinse liquid and rinse water are interchangeable and refer to water supplied from the household water supply 32 that has not been mixed with a treating agent prior to being applied to the laundry. The terms recirculated liquid and recirculated water refer to water or a combination of water and one or more treating agents that is pumped from the sump 16 and re-applied to the laundry, with or without the addition of additional rinse liquid from the household water supply 32.

The washing machine 10 also includes a control system for controlling the operation of the washing machine 10 to implement one or more cycles of operation. The control system may include a controller 60 located within the cabinet 12 and a user interface 62 that is operably coupled with the controller 60. The user interface 62 may include one or more knobs, dials, switches, displays, touch screens and the like for communicating with the user, such as to receive input and provide output. The user may enter different types of information including, without limitation, cycle selection and cycle parameters, such as cycle options.

The controller 60 may include the machine controller and any additional controllers provided for controlling any of the components of the washing machine 10. For example, the controller 60 may include the machine controller and a motor controller. Many known types of controllers may be used for the controller 60. The specific type of controller is not germane to the invention. It is contemplated that the controller 60 is a microprocessor-based controller that implements control software and sends/receives one or more electrical signals to/from each of the various working components to effect the control software. As an example, proportional control (P), proportional integral control (PI), and proportional derivative control (PD), or a combination thereof, a proportional integral derivative control (PID control), may be used to control the various components.

As illustrated in FIG. 2, the controller 60 may be provided with a memory 70 and a central processing unit (CPU) 72. The memory 70 may be used for storing the control software that is executed by the CPU 72 in implementing a cycle of operation using the washing machine 10 and any additional software. Examples, without limitation, of cycles of operation include: wash, heavy duty wash, delicate wash, quick wash, pre-wash, refresh, rinse only, and timed wash. A common wash cycle includes a wash phase, a rinse phase, and a spin extraction phase. Other phases for cycles of operation include, but are not limited to, intermediate extraction phases, such as between the wash and rinse phases, and a pre-wash phase preceding the wash phase, and some cycles of operation include only a select one or more of these exemplary phases.

The memory 70 may also be used to store information, such as a database or table, and to store data received from one or more components of the washing machine 10 that may be communicably coupled with the controller 60. The database or table may be used to store the various operating parameters for the one or more cycles of operation, including factory default values for the operating parameters and any adjustments to them by the control system or by user input.

The controller 60 may be operably coupled with one or more components of the washing machine 10 for communicating with and controlling the operation of the component to complete a cycle of operation. For example, the controller 60 may be operably coupled with the motor 22, the pump 34, and the spraying system 30 to control the operation of these and other components to implement one or more of the cycles of operation.

The previously described washing machine 10 may be used to implement one or more embodiments of the invention. The embodiments of the method of the invention may be used to control the operation of the washing machine 10 to detect the formation of surfactant foam or suds in the tub 14 to mitigate a potential suds lock condition. As used herein, mitigating a suds lock condition may include decreasing the formation of suds and/or removing suds from the tub 14 such that a suds lock condition is avoided or the effect of the suds on the tub 14 and wash basket 18 is decreased.

A typical wash cycle includes a wash phase in which a wash liquid, e.g., a mixture of water and surfactants (and optionally other treating agents), is applied to the laundry, a rinse phase in which the wash liquid is removed from the laundry by rinsing the laundry with rinse liquid, and a spin extraction phase in which at least a portion of the rinse liquid is extracted from the laundry by spinning the laundry at high speeds. A suds lock condition occurs when the wash liquid forms suds and the suds interact with the wash basket 18 and tub 14, causing excess frictional drag between the wash basket 18 and the tub 14. The excess frictional drag may inhibit the wash basket 18 from accelerating to a desired wash basket rotation speed, such as a final or spin extraction rotation speed in which the laundry is rotated at high speeds to extract liquid from the laundry. The methods described herein may be used to detect an over suds condition that can lead to a suds lock condition prior to the rinse phase.

Referring now to FIG. 3, a flowchart of a method 100 for detecting an over suds condition during a cycle of operation is illustrated. The method 100 may be used during a wash cycle or any other cycle of operation in which wash liquid has been applied to the laundry. The method 100 may be implemented as part of a wash or rinse phase of a wash cycle or may be implemented as a separate phase. The sequence of steps depicted for this method is for illustrative purposes only, and is not meant to limit the method in any way as it is understood that the steps may proceed in a different logical order or additional or intervening steps may be included without detracting from the invention.

The method 100 starts with assuming that a cycle of operation in which a wash liquid is applied to the laundry in the treating chamber 19, such as a wash cycle, has not yet been implemented. At 102, the controller 60 implementing the method 100 may measure a baseline fill level in the treating chamber 19. The baseline fill level is the initial level of liquid in the treating chamber 19 before wash liquid is introduced for the cycle of operation. The controller 60 may monitor the fill level of the wash liquid in the treating chamber 19 by sampling a sensor such as a pressure transducer (not shown) located in the treating chamber 19. An example pressure transducer and sampling rate that may be used is the Panasonic ADP51B62 sampled once every 63 ms. Other fluid level sensing technologies and sampling rates may be used depending upon the implementation.

At 104, the fill and wash steps of the cycle of operation may be completed. During these steps, wash liquid may be introduced in the treating chamber 19.

At 106, the pump 34 may drain the wash liquid from the treating chamber 19. The operation of draining the treating chamber 19 may continue until the processor 60 determines the treating chamber 19 is empty. The controller 60 may determine that the treating chamber 19 is empty by sampling the fill level of the treating chamber 19 as the wash liquid is being drained and comparing the sampled fill level to the baseline fill level from 102. When the sampled fill level is less than or equal to the baseline fill level from 102, the controller 60 may consider the treating chamber 19 to be empty.

Once the difference between the sampled fill level and the baseline fill level is zero, the controller 60 may start a timer at 108 for a predetermined period. The predetermined time period may be determined by the particular physical characteristics of an implementation of the washer. A predetermined time period of 60 seconds may be used but other predetermined time periods are possible depending upon the specific implementation.

For the duration of the predetermined time period, the controller 60 may sample the fill level of the treating chamber 19 and store the minimum fill level. The controller 60 may make a check to determine if the predetermined time period has expired at 110, and if it has not, may determine if the currently sampled fill level is less than the current minimum fill level for the predetermined time period. If the currently sampled fill level is less than the current minimum fill level for the predetermined time period, then the controller 60 may update the stored minimum fill level for the predetermined time period to be the currently sampled fill level at 112. By repeating the steps at 110 and 112 until the expiration of the predetermined time period at 110, the controller 60 may determine the minimum fill level in the treating chamber 19 for the predetermined time period. After the predetermined time period has expired, the controller 60 may stop draining the treatment chamber 19 at 114 and sample a final fill level at 116.

At 118, the controller 60 may calculate the difference between the minimum fill level and the final fill level by subtracting the minimum fill level during the predetermined time period from the final fill level. If the difference is greater than a predetermined threshold as calculated at 120, the controller 60 may identify at 122 that a suds lock condition may occur due to an excessive amount of suds. The predetermined threshold may be determined by the particular physical characteristics of an implementation of the washer.

The controller 60 may then take action at 124 to mitigate or avoid a suds lock condition. For example, upon the identification of a potential suds lock condition, the controller 60 may rotate the wash basket in a progressive rinse phase of the wash cycle. The controller 60 may take other actions to mitigate the potential suds lock condition depending upon the specific implementation.

If, at 120, the difference is not greater than a predetermined threshold, the controller 60 may not identify a potential suds lock condition at 126. The controller 60 may then continue to a normal phase of the cycle of operation at 128. For example, the controller 60 may rotate the wash basket in a deep rinse phase of the wash cycle.

Referring now to FIG. 4, an exemplary treating chamber fill level profile 200 is illustrated. The treating chamber fill level profile 200 illustrates the fill level of the treating chamber 19 during implementation of the method 100 of FIG. 3 in the course of a cycle of operation. The treating chamber fill level profile 200 may not be indicative of actual data, but is included for the purposes of illustration.

FIG. 4 illustrates the drain phase of a wash cycle 200 where excessive suds that may lead to a suds lock condition may be present. The profile shown is digital counts of a pressure sensor indicating fill level of a treating chamber 19 versus time in seconds. The fill level is shown to be decreasing at 202 as the treating chamber 19 drains. At 204, the controller 60 may determine the treating chamber is empty and records a baseline fill level. The controller 60 may then continue to sample the fill level for a predetermined period of time and record the minimum fill level at 206. When the predetermined period of time ends, the controller 60 may sample a final fill level and compare to the minimum fill level. If the controller 60 determines the minimum fill level at 206 is below the final fill level by a predetermined threshold, it may identify excessive suds that may lead to an suds lock condition and take appropriate action to mitigate or avoid a suds lock condition.

The methods described herein may be used to detect and mitigate the formation of a suds lock condition in a washing machine. Excess suds in a washing machine may increase the frictional drag between the wash basket and the tub, which may result in the wash basket not reaching a desired rotational speed or may require additional energy to reach the desired rotation speed, which may increase energy costs during the cycle. During a spin extraction phase, the wash basket is rotated at high speeds to remove liquid from the laundry for subsequent treatment or drying. If the wash basket cannot be rotated at the desired spin extraction speed due to a suds lock condition, it may take longer to extract liquid from the laundry, which may provide an undesirable lengthening of the cycle, or the laundry may maintain more liquid at the end of the cycle, which may be undesirable to the user. The methods described herein may be used to identify a potential suds lock condition before it occurs and decrease the interaction between the tub and the wash basket during rotation of the wash basket.

To the extent not already described, the different features and structures of the various embodiments may be used in combination with each other as desired. That one feature may not be illustrated in all of the embodiments is not meant to be construed that it cannot be, but is done for brevity of description. Thus, the various features of the different embodiments may be mixed and matched as desired to form new embodiments, whether or not the new embodiments are expressly described.

While the invention has been specifically described in connection with certain specific embodiments thereof, it is to be understood that this is by way of illustration and not of limitation. Reasonable variation and modification are possible within the scope of the forgoing disclosure and drawings without departing from the spirit of the invention which is defined in the appended claims. 

What is claimed is:
 1. A method for detecting an over suds condition that can lead to a suds lock condition in a laundry treating appliance having a tub defining an interior, with a wash basket rotatably mounted within the interior and at least partially defining a treating chamber for receiving laundry for treatment in accordance with a cycle of operation using a wash liquid, the method comprising: determining a baseline fill level in the treating chamber prior to introducing wash liquid into the treating chamber in the cycle of operation; sampling fill levels of the wash liquid in the treating chamber during a wash phase of the cycle of operation while wash liquid is being drained from the treating chamber; comparing each sampled fill level to the baseline fill level and determining a difference; continuing to sample fill levels in the treating chamber for a predetermined period after the difference equals zero; identifying a minimum fill level in the treating chamber for the predetermined period; sampling a final fill level after the predetermined period; calculating a difference between the minimum fill level and the final fill level; and identifying a suds lock condition if the difference exceeds a predetermined threshold.
 2. The method of claim 1 including the step of rotating the wash basket in a progressive rinse cycle if a potential suds lock condition is identified.
 3. The method of claim 1 including the step of rotating the wash basket in a deep or normal rinse cycle if a suds lock condition is not identified.
 4. The method of claim 1 wherein the predetermined time period is 60 seconds.
 5. The method of claim 1 wherein the predetermined time period is determined by the physical characteristics of the laundry treating appliance.
 6. The method of claim 1 wherein the step of sampling fill levels in the treating chamber occurs at a rate
 7. The method of claim 1 wherein the step of sampling fill levels in the treating chamber is determined by the physical characteristics of the laundry treating appliance.
 8. The method of claim 1 wherein a pressure transducer is used in the steps of determining a baseline fill level in the treating chamber and continuing to sample fill levels in the treating chamber for a predetermined period, and sampling a final fill level after the predetermined period.
 9. The method of claim 1 wherein a controller is used to digitize analog measurements made during the steps of determining a baseline fill level in the treating chamber, continuing to sample fill levels in the treating chamber for a predetermined period, and sampling a final fill level after the predetermined period.
 10. The method of claim 1 wherein a controller is used in the steps of identifying the minimum fill level in the treating chamber for the predetermined period, calculating a difference by subtracting the minimum fill level from the final fill level; and identifying a potential suds lock condition if the difference exceeds a predetermined threshold. 